One think that I think they provide (as opposed to the self hosted version) is just the fact of being a relatively neutral third party.

If there’s a dispute over the veracity of a signature, it’s probably helpful to have a third party say “according to our server logs and software stack, this was signed by johndoe@example.com at 12:41pm on August 3rd, from the IP address XX.XXX.XXX.XX, and they authenticated with their email and password”. If I’m self-hosting, it’s marginally less convincing when I’m before a court if I say *my* software stack says that, since I have more direct control over it.

So, I agree DocuSign doesn’t have a special status, other than being a relatively neutral third party to that dispute. But if a signature’s validity is being questioned, that third party status is probably somewhat helpful.